** unique object **
Radiosystem Sweden AB
In working and very good condition
This kit was used in the field by a field engineer.
You can switch between NMT 450 and NMT 900 network
NMT was a Scandinavian cellular network, developed by and used in Scandinavian countries. If was used in the Baltic countries, Switzerland, Netherlands, Hungary, Poland, Bulgaria, Romania, Czech Republic, Slovakia, Slovenia, Serbia, Turkey, Croatia, Bosnia, Russia, Ukraine and in Asia. The NMT network was opened in Sweden and Norway in 1981, and in Denmark and Finland in 1982. Iceland joined in 1986. Networks where shut down in 2000 (Estonia), 2002 (Finland), 2004 (Norway), 2007 (Sweden), 2010 (Iceland). It was a cellular system, so frequencies could be used efficiently. It offered handover capability, so moving phones could change cells during a call. Authentication was introduces (SIS), to prevent fraud, but it was optional. Older phones without SIS could be cloned by receiving and decoding the roaming update message. Extra services (e. g. conditional call forwarding, answering machine) were installed in the mobile exchange. Phones were build in cars but also hand-held phones were available. All phones were available under a dedicated prefix, so the caller must only dial the phone number to reach the phone anywhere. The networks offered a data service (DMS) that re-used the signaling modem to transfer data to a terminal or PC. This data service was used to transfer short messages (SMS) between service center (SMSC) and the mobile phone.
The Mobile Telephone Exchange (MTX) is the brain of the system and is technically the most complicated part. Several MTXs form the interface between the NMT system and the fixed telephone network. Whereas signaling and other system components of NMT are the same in all countries, their telephone networks differ in some respects. One of the functions of the MTXs is therefore to compensate for these differences.
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